GMAW welding torches typically comprise a mounting block adapted to be manipulated by a welder's hand or a robotic manipulator, made of current conducting material such as aluminum or a copper alloy. A current conducting barrel, having a welding tip at the remote end thereof, is generally inserted into a socket formed in the block. The barrel is secured in the block by means of bolts which squeeze two sides of the block, separated by a slit, together adjacent the entrance to the socket. The mounting block transfers a consumable electrode or welding wire, weld current, inert gas and generally a coolant fluid such as water, from a stationary location, e.g., a cabinet, to the barrel. The barrel is provided with appropriate passageways or channels for conducting such materials to the welding tip. See U.S. Pat. No. 4,954,690 which describes the GMAW torch sold by the assignee of this application, M. K. Products, Inc., under the trademark Prince.RTM.. The Prince.RTM. torch does not provide a coolant liquid to the barrel. Also see U.S. Pat. No. 5,549,068 which describes another torch marketed by M. K. Products under the trademark King Cobra.RTM.. The latter torch, which is water cooled, utilizes intermediate barrel mounted to the block for holding the torch barrel.
Torch barrels may be straight or curved depending upon the type of welding to be accomplished and the preferences of the welder. It is often necessary or highly desirable for an operator to be able to change the angular position of a curved barrel relative to the block to accommodate a robotic manipulator or to configure the torch so that it is more ergonomically compatible to a welder's hand manipulations.
The barrels in both of the above prior art torches can be rotated. However, a proper tool is used to remove the cover and adjust the angular position of the '690 torch. An angular adjustment of the barrel in the '068 torch can be readily accomplished by hand. However, the intermediate barrel (referred to in the '068 patent as the main barrel) constitutes not only an additional element, but an element that is expensive to manufacture in view of the bayonet connections (22a and 22b, FIG. 3) for the cooling water. In addition, arcing can occur between metallic collet fingers (100, FIG. 5) and the welding tip barrel mounting structure (34, FIG. 3) of the '068 torch if the operator fails to insure that the collet nut 20 is rotated to its tightened stop position.
There is a need for an improved GMAW torch assembly which allows an operator to readily rotate a weld tip barrel (particularly of the curved type) without disturbing the feed wire, gas and coolant connections while insuring that a reliable current carrying connection between the barrel and block is maintained after the rotation has been accomplished.